To make diagnoses from imaging technologies such as computerized tomography (CT) and magnetic resonance imaging (MRI), radiologists use 2D image planes that slice through these data at a variety of angles to obtain the most clinically informative view. However, current approaches used to orient the 2D image plane within the 3D data are cumbersome and visually distracting. Typically, current commercial medical workstations require several mouse interactions with multiple reference images to select, drag, and rotate reference lines or buttons as part of this process.

Professor David J. Lomas from the Department of Radiology at Cambridge University and Dr. Martin Graves of Cambridge University Hospitals NHS Foundation Trust have developed a novel human interface device called the Constrained Surface (CS) Controller that can be used to navigate volumetric image data while avoiding visual distraction.

The mode of action of the CS Controller is based upon clinical experience of performing real-time ultrasound examinations. In ultrasound, a handheld imaging transducer is moved smoothly over the body surface while the operator concentrates on the output image on a display. Experienced operators know automatically where the imaging plane is positioned because they know where their hands are positioned in space, and because the motion of the transducer in relation to the body is limited by the constraining surface of the subject’s skin. The operator integrates this information with his or her knowledge of the body’s internal anatomy and learns to obtain desired image planes within the 3D volume of the patient’s body by watching the output image on the display as the transducer is moved.

The team worked with EG Technology, a product design, development, and engineering consultancy, to develop a working prototype. The controller applies the constraining surface concept to the navigation of previously acquired 3D volumetric image data within a workstation. The result is a device that allows intuitive control of the reformatting plane location without the distraction of interacting with the workstation tools.

The CS Controller has also been successfully integrated into research MRI fluoroscopy systems to allow interactive positioning of an acquired real-time image plane in patients, in a similar fashion to ultrasound.

This technology was done by the University of Cambridge, Cambridge, UK. Cambridge Enterprise, a subsidiary of the University of Cambridge, is seeking commercial partners for licensing, collaboration, and development of this technology. For more information, visit